With the rise of three-dimensional (3D) display products, holographic display products and other special display products, a crucial demand on devices has been raised—light modulation. As shown in FIG. 1, it is a schematic diagram of an optical path adjustment of a light guide plate with micro structures in the related art. As shown in FIG. 1, the lights emitted by the light source are reflected on the micro structures of the light guide plate to form collimated lights. The collimated lights may be utilized to realize devices such as 3D display or holographic display.
At present, the main process for manufacturing the micro structures is a Lithography-Electro-Injection-Injection (LIGA) process. The LIGA process includes the following steps. First, a photoresist master mold is formed on a base substrate and the surface of the photoresist master mold is processed with conduction treatment. After that, the above-mentioned photoresist master mold is used to form a mold through an electroforming process and a demolding process. Afterwards, a pattern of micro structures is formed by pressing the mold. Then, a high anti-metal sputtering is performed on the pattern of the micro structures to make them has reflection function. Afterwards, the tips of the micro structures are removed through a sharpening process to achieve the light transmission function of the micro structures. Otherwise, the light cannot enter the micro structures to achieve reflection.
However, since the micro structures are generally structures of tens of micrometers, overall sharpening cannot be performed like on a macro structure. In addition, in order to ensure that all the micro structures are closely connected with the light guide plate, to achieve the adhesion precision between the micro structures and the light guide plate, it is required that the tips of the micro structures processed by the sharpening process have high flatness and a high degree of uniformity, which has a high requirement on the sharpening process. There is no suitable sharpening process yet in the related art which can achieve high adhesion precision between the micro structures and the light guide plat.